The following short guide is necessarily worded in a general way and cannot cover every circumstance. It is intended only as a guide for manufacturers, suppliers and installers of new and replacement glass and glazing products for domestic use. Additionally the content is relevant to UK - domestic situations only.
Where glass and glazing products are supplied for domestic use (such as conservatories, garages, double glazing, porches) they must comply with the 'General Safety Requirement' of the General Product Safety Regulations 1994 (GPSR). This requires consumer products to be reasonably safe and this may be achieved by conforming with British Standard BS 6262: Part 4: 1994 (as detailed below) with reference to the Approved Document N of the Building Regulations 1991.
WHAT GLAZING MUST BE SAFE?
The updated British Standard "BS 6262: Part 4: 1994 Code of Practice for Glazing for Buildings", introduced new requirements that glazing fitted in 'critical locations' in domestic buildings must be safe.
This may be achieved for example by fitting glass which breaks safely; small panes of ordinary glass; thicker ordinary glass; by protecting the glass with a permanent robust screen; or using plastics glazing sheet. Further details are given below.
WHAT IS A CRITICAL LOCATION?
Certain internal and external areas are considered 'critical locations' in terms of the safety of vertical glazing, as they are at risk from accidental human impact. The critical locations defined by the standard are similar to the Approved Document N of the Building Regulations 1991.
Doors
Any glazing or part of that glazing in a door, which is between the finished floor level and a height of 1500mm above the floor level, is in a 'critical location'
Side panels to doors
Any glazing or part of that glazing, which is within 300mm of either side of a door edge and which is between the finished floor level and a height of 1500mm above the floor level, is in a 'critical location'.
Windows, partitions and walls
Any glazing or part of that glazing, which is between the finished floor level and a height of 800mm above the floor level, is in a 'critical location'.
Roof glazing
Any overhead glazing or roof glazing is deemed as a 'critical location'
Public spaces
Any public space, school, pub, hospital, shopping area is deemed as a 'critical location'
All shaded areas in the below diagram need to have safety glazing
Glazing in small panes: The use of annealed (non-safety) glass is permitted in small panes. These panes should have a maximum width of 250mm and an area not exceeding 0.5m2when measured between the glazing beads. Annealed glass in a small pane should not be less than 6mm thick except in traditional leaded or copper lights where 4mm glass can be used if fire resistance is not required.
Dimensions and Areas of Small Panes
The maximum area of single pane is not to exceed 0.5m2, and small panes of annealed glass should not be less than 6mm thick.
Visual quality standards for installed insulating glass units constructed from flat transparent glass
Transparent glass used in the manufacture of insulating glass unit is identical to that used traditionally for single glass will therefore have a similar level of quality.
Both panes of sealed unit shall be viewed at right angles to the glass from the room standing at a distance of not less than 2 metres for toughened, laminated or coated glass, not less than a distance of 3 metres in natural daylight and not in direct sunlight.
Flat transparent glass, including laminated or toughened (tempered) glass shall be deemed acceptable if the following phenomena are neither obstrusive nor bunched: totally enclosed seeds, bubbles or blisters: hairlines or blobs: fine scratches not more than 25mm long;minute embedded particles
When thermally toughened glass is viewed by reflection, the effect of the toughening process may be seen under certain lighting conditions. The viability of surface colouration or patterns does not indicate deterioration in the physical performance of the toughened glass. Because of the nature of the toughening process, distortion can be introduced. Such distortion will be accentuated when the glass viewed in reflection or incorporated in insulating glass units.
Visible double reflection can occur under certain lighting aspect conditions. Especially when viewed from an angle. This is an optical phenomenon arising from the multiple surface reflection in sealed units.
The manufacture of flat laminated glass does not usually affect the visual quality of the glass incorporated in insulating glass units. However, the faults generally accepted in paragraph 3 may be increased in number by the fact that several glasses and interlayers are used in the production of laminated glass. When viewed under certain lighting conditions, insulating glass units incorporating clear or tinted flat laminated glass may show distortion effect caused by reflection on the multiple surfaces of the components of the laminated glass.